Cardiovascular Emergencies
Chapter 17
Objectives
- Describe the structure and function of the cardiovascular system.
- Describe the emergency medical care of the patient experiencing chest pain/discomfort.
- List the indications for automated external defibrillation (AED).
- List the contraindications for automated external defibrillation.
- Define the role of EMT-B in the emergency cardiac care system.
- Explain the impact of age and weight on defibrillation.
- Discuss the position of comfort for patients with various cardiac emergencies.
- Establish the relationship between airway management and the patient with cardiovascular compromise.
- Predict the relationship between the patient experiencing cardiovascular compromise and basic life support.
- Discuss the fundamentals of early defibrillation.
- Explain the rationale for early defibrillation.
- Explain that not all chest pain patients result in cardiac arrest and do not need to be attached to an automated external defibrillator.
- Explain the importance of prehospital ACLS intervention if it is available.
- Explain the importance of urgent transport to a facility with Advanced Cardiac Life
Support if it is not available in the prehospital setting.
- Discuss the various types of automated external defibrillators.
- Differentiate between the fully automated and the semiautomated defibrillator.
- Discuss the procedures that must be taken into consideration for standard operations of the various types of automated external defibrillators.
- State the reasons for assuring that the patient is pulseless and apneic when using the automated external defibrillator.
- Discuss the circumstances which may result in inappropriate shocks.
- Explain the considerations for interruption of CPR, when using the automated external defibrillator.
- Discuss the advantages and disadvantages of automated external defibrillators.
- Summarize the speed of operation of automated external defibrillation.
- Discuss the use of remote defibrillation through adhesive pads.
- Discuss the special considerations for rhythm monitoring.
- List the steps in the operation of the automated external defibrillator.
- Discuss the standard of care that should be used to provide care to a patient with persistent ventricular fibrillation and no available ACLS.
- Discuss the standard of care that should be used to provide care to a patient with recurrent ventricular fibrillation and no available ACLS.
- Differentiate between the single rescuer and multi-rescuer care with an automated external defibrillator.
- Explain the reason for pulses not being checked between shocks with an automated external defibrillator.
- Discuss the importance of coordinating ACLS trained providers with personnel using automated external defibrillators.
- Discuss the importance of post-resuscitation care.
- List the components of post-resuscitation care.
- Explain the importance of frequent practice with the automated external defibrillator.
- Discuss the need to complete the Automated Defibrillator: Operator's Shift Checklist.
- Discuss the role of the American Heart Association (AHA) in the use of automated external defibrillation.
- Explain the role medical direction plays in the use of automated external defibrillation.
- State the reasons why a case review should be completed following the use of the automated external defibrillator.

Objectives Continued
- Discuss the components that should be included in a case review.
- Discuss the goal of quality improvement in automated external defibrillation.
- Recognize the need for medical direction of protocols to assist in the emergency medical care of the patient with chest pain.
- List the indications for the use of nitroglycerin.
- State the contraindications and side effects for the use of nitroglycerin.
- Define the function of all controls on an automated external defibrillator, and describe event documentation and battery defibrillator maintenance.
- Defend the reasons for obtaining initial training in automated external defibrillation and the importance of continuing education.
- Defend the reason for maintenance of automated external defibrillators.
- Explain the rationale for administering nitroglycerin to a patient with chest pain or discomfort.
I. Review of Circulatory System Anatomy and Physiology
A. Circulatory (Cardiovascular)
1. Heart a. Structure/function
(1) Atrium
(a) Right - receives blood from the veins of the body and the heart and pumps oxygen-poor blood to the right ventricle.
(b) Left - receives blood from the pulmonary veins (lungs) and pumps oxygen-rich blood to left ventricle.
(2) Ventricle
(a) Right - pumps blood to the lungs.
(b) Left - pumps blood to the body.
(3) Valves prevent backflow of blood. b. Cardiac conductive system
(1) Heart is more than a muscle.
(2) Specialized contractile and conductive tissue in the heart
(3) Electrical impulses
2. Arteries a. Function - carry blood away from the heart to the rest of the body. b. Major Arteries
(1) Coronary arteries - vessels that supply the heart with blood.
(2) Aorta
(a) Major artery originating from the heart and lying in front of the spine in the thoracic and abdominal cavities.
(b) Divides at the level of the navel into the iliac arteries.

(3) Pulmonary
(a) Artery originating at the right ventricle.
(b) Carries oxygen-poor blood to the lungs.
(4) Carotid
(a) Major artery of the neck
(b) Supplies the head with blood.
(c) Pulsations can be palpated on either side of the neck.
(5) Femoral
(a) The major artery of the thigh
(b) Supplies the groin and the lower extremities with blood.
(c) Pulsations can be palpated in the groin area.
(6) Radial
(a) Major artery of the lower hand
(b) Pulsations can be palpated at the wrist thumb side.
(7) Brachial
(a) An artery of the upper arm
(b) Pulsations can be palpated on the inside of the arm between the elbow and the shoulder.
(c) Used when determining a blood pressure
(BP) using a BP cuff (sphygmomanometer) and a stethoscope.
(8) Posterior tibial - pulsations can be palpated on the posterior surface of the medial malleolus.
(9) Dorsalis pedis
(a) An artery in the foot
(b) Pulsations can be palpated on the anterior surface of the foot.
3. Arterioles - the smallest branches of an artery leading to the capillaries.
4. Capillaries a. Tiny blood vessels that connect arterioles to venules. b. Found in all parts of the body c. Allow for the exchange of nutrients and waste at the cellular level.
5. Venules - the smallest branches of the veins leading to the capillaries.
6. Veins a. Function - vessels that carry blood back to the heart. b. Major veins
(1) Pulmonary vein - carries oxygen-rich blood from the lungs to the left atrium.

(2) Venae Cavae
(a) Superior
(b) Inferior atrium.
(c) Carries oxygen-poor blood back to the right
7. Blood composition a. Red blood cells
(1) Give the blood its color.
(2) Carry oxygen to organs.
(3) Carry carbon dioxide away from organs. b. White blood cells - part of the body's defense against infections. c. Plasma - fluid that carries the blood cells and nutrients. d. Platelets - essential for the formation of blood clots.
8. Physiology a. Pulse
(1) Left ventricle contracts sending a wave of blood through the arteries.
(2) Can be palpated anywhere an artery simultaneously passes near the skin surface and over a bone.
(3) Peripheral
(a) Radial
(b) Brachial
(c) Posterior tibial
(d) Dorsalis pedis
(4) Central
(a) Carotid
(b) Femoral b. Blood Pressure
(1) Systolic - the pressure exerted against the walls of the artery when the left ventricle contracts.
(2) Diastolic - the pressure exerted against the walls of the artery when the left ventricle is at rest.
B. Inadequate circulation - Shock (hypoperfusion): A state of profound depression of the vital processes of the body. Characterized by signs and symptoms such as: Pale, cyanotic, cool clammy skin, rapid but weak pulse, rapid and shallow breathing, restlessness, anxiety or mental dullness, nausea and vomiting, reduction in total blood volume, low or decreasing blood pressure and subnormal temperature.
II. Cardiac Compromise - Signs and Symptoms. May include one or all of the following:
A. Squeezing, dull pressure, chest pain commonly radiating down the arms or to the jaw.
B. Sudden onset of sweating (this in and of itself is a significant finding).
C. Difficulty breathing (dyspnea)

D. Anxiety, irritability
E. Feeling of impending doom
F. Abnormal pulse rate (may be irregular)
G. Abnormal blood pressure
H. Epigastric pain
I. Nausea/vomiting
III. Cardiovascular Emergencies
A. Most Common Cause of Cardiovascular Emergencies
1. Atherosclerosis – Hardening of the Vessels
B. Acute Myocardial Infarction (AMI or MI) – Heart Attack
1. Caused by the blockage of an artery supplying blood to the myocardium
2. Risk Factors a. Smoking b. Hypertension c. Increased cholesterol d. Diabetes e. Lack of exercise f. Stress g. Age h. Family history i. Sex
3. Signs/Symptoms a. Chest pain (crushing, squeezing) (most common symptom) b. Radiating pain (arms, neck, jaw, epigastric, back) c. Dyspnea d. Anxiety/Sense of impending doom e. Nausea/vomiting f. Diaphoresis g. Weakness h. Pulmonary edema (rales) i. Diabetics/Elderly may not feel pain with AMI (silent MI)
4. Treatment a. Reassure the patient b. Apply O2 c. Get a pulse oximetry reading prior to O2 administration d. Position of comfort (usually sitting upright) e. DO NOT allow patient to exert themselves (walk to cot) f. Vitals
(1) Reassess every 5 minutes or whenever condition changes g. Physical exam h. History
(1) OPQRST
(2) SAMPLE

i. Gather medications j. Assist with nitro if available and within protocols k. Transport
C. Angina Pectoris
1. A symptom of atherosclerotic coronary artery disease
2. Occurs when the Hearts need for O2 exceeds its supply
3. Risk factors - Same as for AMI
4. Signs/symptoms - Same as for AMI
5. Treatment – Same as for AMI
D. AMI vs. Angina
1. AMI a. May or may not be caused by exertion b. Pain may or may not go away with rest and/or nitro c. Pain does not go away in a few minutes
2. Angina a. Usually caused by exertion or activity b. Pain disappears with rest and/or Nitro
E. Consequences of AMI
1. Sudden death a. 40% of all patients never reach the hospital
2. Cardiac rhythms seen prior to arrest a. Ventricular fibrillation (V-fib)
(1) Quivering of the heart, electrical impulses are originating from all areas of the heart
(2) Treatment of choice is defibrillation (AED) b. Tachycardia
(1) Heart rate >100 c. Bradycardia
(1) Heart rate <60 d. Ventricular Tachycardia (V-tach)
(1) Rhythm originating in the ventricles at a rate of
>150bpm
(2) If pulseless it is treated the same as ventricular fibrillation
F. Congestive Heart Failure
1. Ventricles of heart are unable to keep up with blood flow from atria
2. Signs/symptoms a. Anxiety/restlessness b. Dyspnea, especially when lying down c. Tachycardia d. Tachypnea e. Increased blood pressure f. Accessory muscle use

g. Jugular venous distention (JVD) h. Pedal edema i. Lung sounds – rales
3. Treatment a. Position of comfort b. High flow O2 c. Assist ventilations as needed d. Consider Nitro
– follow protocols e. Rapid transport
G. Cardiogenic Shock
1. Signs/symptoms a. Anxiety/restlessness b. Pale/cool/diaphoretic skin c. Tachycardia d. Dyspnea e. Blood pressure <90 systolic f. Lung sounds - rales
2. Treatment a. Position of comfort while maintaining perfusion b. High flow O2 c. Assist ventilations as needed d. Rapid transport
IV. Emergency Medical Care - Initial Patient Assessment Review
A. Circulation - pulse absent
1. Medical patient >12 years old - CPR with AED
2. Medical patient < 12 years old or < 90 lbs. - CPR
B. Responsive patient with a known history - cardiac
1. Perform initial assessment.
2. Perform focused history and physical exam.
3. Place patient in position of comfort.
4. Cardiac a. Complains of chest pain/discomfort.
(1) Apply oxygen if not already done.
(2) Assess baseline vital signs. b. Important questions to ask.
(1) Onset
(2) Provocation
(3) Quality
(4) Radiation
(5) Severity
(6) Time

c. Has been prescribed nitroglycerin (NTG) and nitro is with the patient.
(1) Blood pressure greater than 100 systolic
(a) One dose, repeat in 3-5 minutes if no relief and authorized by medical direction up to a maximum of three doses.
(b) Reassess vital signs and chest pain after each dose.
(2) Blood pressure less than 100 systolic - continue with elements of focused assessment. d. Does not have prescribed nitroglycerin (NTG)
– continue with elements of focused assessment. e. Transport promptly
V. Medications
A. Nitroglycerin
1. Medication name a. Generic - nitroglycerin b. Trade - Nitrostat
2. Indications - must have all of the following criteria: a. Exhibits signs and symptoms of chest pain, b. Has physician prescribed sublingual tablets, and c. Has specific authorization by medical direction.
3. Contraindications a. Hypotension or blood pressure below 100 mmHg systolic. b. Head injury c. Infants and children d. Sexual Enhancement Drugs in the last 24 – 48 hours e. Patient has already met maximum prescribed dose prior to EMT-Basic arrival.
4. Medication form - tablet, sub-lingual spray
5. Dosage - one dose, repeat in 3-5 minutes if no relief, BP > 100, and authorized by medical direction up to a maximum of three doses.
6. Administration a. Obtain order from medical direction either on-line or offline. b. Perform focused assessment for cardiac patient. c. Take blood pressure - above 100 mmHg systolic.
d. Contact medical control if no standing orders. e. Assure right medication, right patient, right route, patient alert. f. Check expiration date of nitroglycerin. g. Question patient on last dose administration, effects, and assures understanding of route of administration.

h. Ask patient to lift tongue and place tablet or spray dose under tongue (while wearing gloves) or have patient place tablet or spray under tongue. i. Have patient keep mouth closed with tablet under tongue
(without swallowing) until dissolved and absorbed. j. Recheck blood pressure within 2 minutes. k. Record activity and time. l. Perform reassessment.
7. Actions a. Relaxes blood vessels b. Decreases workload of heart
8. Side effects a. Hypotension b. Headache c. Pulse rate changes
9. Reassessment strategies a. Monitor blood pressure. b. Ask patient about effect on pain relief. c. Seek medical direction before re-administering. d. Record reassessments.
VI. Relationship to Basic Life Support
A. Not all chest pain patients become cardiac arrest patients.
B. One Rescuer CPR - rarely done by EMT-Basics while on duty, may be done while partner is preparing equipment, or en route to facility.
C. Two Rescuer CPR - learning outcomes of a Professional Rescuer CPR
Course must be enhanced during an EMT-Basic course.
1. EMT-Basics must also learn: a. Use of automated external defibrillation. b. To request available ALS backup to continue the chain of survival (as developed by AHA) when appropriate. c. Use of bag-valve-mask devices with oxygen attached. d. Use of flow restricted, oxygen-powered ventilatory devices. e. Techniques of lifting and moving patients. f. Suctioning of airways. g. Use of airway adjuncts. h. Use of body substance isolation for infections whe necessary. i. Interviewing bystanders/family to obtain facts related to arrest events.
VII. Automated External Defibrillation
A. Importance of automated external defibrillation to the EMT-Basic.
1. Fundamentals of early defibrillation - successful resuscitation of out-of-hospital arrest depends on a series of critical interventions known as the chain of survival. a. Early access

b. Early CPR c. Early defibrillation d. Early ACLS
2. Rationale for early defibrillation a. Many EMS systems have demonstrated increased survival outcomes of cardiac arrest patients experiencing ventricular fibrillation. b. This increased survival was after early defibrillation programs were implemented and when all of the links in the chain of survival were present.
B. Overview of automated external defibrillators
1. Types of automated external defibrillators a. Fully automated - defibrillator operates without action by
EMT-Basic, except to turn on power. b. Semi-automated - defibrillator uses a computer voice synthesizer to advise EMT-Basic as to the steps to take based upon its analysis of the patient's cardiac rhythm. c. Monophasic
– Shocks in one direction, uses higher energy d. Biphasic – Shocks in 2 directions, uses lower energy
2. Analysis of cardiac rhythms a. Defibrillator computer microprocessor evaluates the patient's rhythm and confirms the presence of a rhythm for which a shock is indicated. b. Accuracy of devices in rhythm analysis has been high both in detecting rhythms needing shocks and rhythms that do not need shocks. c. Analysis is dependent on properly charged defibrillator batteries.
3. Inappropriate delivery of shocks a. Human error b. Mechanical error
4. Ventricular tachycardia a. Attach defibrillator to only unresponsive, pulseless, nonbreathing patients to avoid delivering inappropriate shocks. b. Defibrillator advises shocks for ventricular tachycardia when the rate exceeds a certain value, for example, above
180 beats per minute.
5. Interruption of CPR a. No CPR performed at times shocks are delivered. b. No person should be touching patient when rhythm is being analyzed and when shocks are delivered. c. Chest compressions and artificial ventilations are stopped when the rhythm is being analyzed and when shocks are delivered.

d. Defibrillation is more effective than CPR, so stopping CPR during process is more beneficial to patient outcome. e. CPR may be stopped up to 90 seconds if three shocks are necessary. f. Resume CPR only after up to the first three shocks are delivered.
C. Advantages of automated external defibrillation
1. Initial training and continuing education a. Easier to learn than CPR, however, must memorize treatment sequence. b. EMS delivery system should have:
(1) Necessary links in chain of survival.
(2) Medical direction.
(3) EMS system with audit and/or quality improvement program in place.
(4) Mandatory continuing education with skill competency review for EMS providers. c. Continuing competency skill review every three months for
EMT-Basic.
2. Speed of operation - first shock can be delivered within one minute of arrival at the patient's side.
3. Remote defibrillation through adhesive pads. a. Defibrillation is "hands-off" b. Safer method c. Better electrode placement d. Has larger pad surface area e. Provokes less anxiety in EMT-Basic
4. Rhythm monitoring - option on some defibrillator models.
D. Use of automated external defibrillators during resuscitation attempts.
1. Operational steps a. Take infection control precautions - should be done en route to scene. b. Arrive on scene and perform initial assessment. c. Stop CPR if in progress. d. Verify pulselessness and apnea. e. Have partner resume CPR. f. Attach device. g. Turn on defibrillator power. h. Begin narrative if machine has tape recorder. i. Stop CPR. j. Clear patient.
k. Initiate analysis of rhythm.
(1) Machine advises shock.
(a) Deliver shock.
(b) Re-analyze rhythm.

(c) If machine advises shock, deliver second shock.
(d) Re-analyze rhythm.
(e) If machine advises shock, deliver third shock.
(f) Check pulse. i) If pulse, check breathing. a) If breathing adequately, give high concentration oxygen by nonrebreather mask and transport. b) If not breathing adequately, artificially ventilate with high concentration oxygen and transport. ii) If no pulse, resume CPR for one minute. a) Repeat one cycle of up to three stacked shocks. b) Transport.
(2) If, after any rhythm analysis, the machine advises no shock, check pulse.
(a) If pulse, check breathing. i) If breathing adequately, give high concentration oxygen by nonrebreather mask and transport. ii) If not breathing adequately, artificially ventilate with high concentration oxygen and transport.
(b) If no pulse, resume CPR for one minute. i) Repeat rhythm analysis. a) If shock advised, deliver if necessary up to two sets of three stacked shocks separated by one minute of CPR. b) If no shock advised and no pulse, resume CPR for one minute. c) Analyze rhythm third time.
- If shock advised, deliver, if needed, up to two sets of three stacked shocks separated by one minute of CPR.
- If no shock advised, resume
CPR and transport.

2. Standard operational procedures a. Assuming no on-scene ALS, the patient should be transported when one of the following occurs:
(1) The patient regains a pulse.
(2) Six shocks are delivered.
(3) The machine gives three consecutive messages
(separated by one minute of CPR) that no shock is advised. b. One EMT-Basic operates defibrillator, one does CPR. c. Defibrillation comes first. Don't hook up oxygen or do anything that delays analysis of rhythm or defibrillation. d. EMT-Basic must be familiar with device used in operational EMS setting. e. All contact with patient must be avoided during analysis of rhythm. f. State "Clear the patient" before delivering shocks. g. No defibrillator is capable of working without properly functioning batteries. Check batteries at beginning of shift.
Carry extra batteries.
3. Age and weight guideline a. Airway and artificial ventilation is of prime importance. b. Automated external defibrillation is not used in cardiac arrest in children under 12 years of age and less than 90 lbs.
4. Persistent ventricular fibrillation and no available ALS backup. a. After six shocks on scene, (three initial, three after one minute of CPR), prepare for transport. b. Additional shocks may be delivered at the scene or en route by approval of local medical direction. c. Automated external defibrillators can not analyze rhythm when emergency vehicle is in motion. Must completely stop vehicle in order to analyze rhythm if more shocks are ordered. d. It is not safe to defibrillate in a moving ambulance.
5. Recurrent ventricular fibrillation - defibrillation with no available
ACLS. a. If en route with unconscious patient check pulse frequently (every 30 seconds). If pulse is not present then:
(1) Stop vehicle.
(2) Start CPR if defibrillator is not immediately ready.
(3) Analyze rhythm.
(4) Deliver shock if indicated.
(5) Continue resuscitation as per protocol. b. If en route with conscious patient having chest pain who becomes unconscious, pulseless and apneic then:
(1) Stop vehicle.
(2) Start CPR if defibrillator is not immediately ready.

(3) Analyze rhythm.
(4) Deliver up to 3 shocks, if indicated.
(5) Continue resuscitation as per protocol. c. If "no shock" message is delivered and no pulse is present
(1) Start or resume CPR.
(2) Analyze rhythm until three consecutive "no shock" messages given or six shocks given or patient regains pulse.
(3) Continue transport.
6. Single rescuer with an automated external defibrillator a. Follow sequence
(1) Perform initial assessment.
(2) Assure pulselessness, apnea.
(3) Turn on AED power.
(4) Attach device.
(5) Initiate analysis of rhythm.
(6) Deliver shock if necessary.
(7) Follow protocol. b. Defibrillation is initial step; CPR should not be performed prior to rhythm analysis. c. EMS system activation should not occur until "no shock indicated", pulse returns, three shocks are delivered, or help arrives.
7. Pulse checks should not occur during rhythm analysis. Typically there will be no pulse check between stacked shocks 1 & 2 and stacked shocks 4 & 5.
8. Coordination of ALS personnel or EMT-Paramedics when EMT-
Basics are using automated external defibrillators. a. EMS system design establishes protocols. b. AED usage does not require ALS on scene. c. ALS should be notified of arrest events as soon as possible. d. Considerations for EMT-Basic transporting the patient or waiting for ALS to arrive on the scene to transport should be in local protocols established by medical direction.
9. Safety considerations a. Water - rain b. Metal c. Medication Patches d. Implanted Devices e. Hairy Chest f. Patient Movement
E. Post resuscitation care
1. After automated external defibrillation protocol is completed, patient may: a. Have pulses.

b. Have no pulse with machine indicating "no shock indicated." c. Have no pulse with machine indicating shock.
2. If pulses return a. See airway module. b. See lifting and moving patients module. c. Consider awaiting ALS backup if appropriate. d. See transportation module. e. Continue to keep defibrillator device on patient en route. f. Perform focused assessment and reassessment en route.
F. Defibrillator maintenance
1. Regular maintenance for defibrillators is necessary.
2. Operators Shift Checklist for Automated Defibrillators must be accomplished on a daily basis by EMT-Basics.
3. Defibrillator failure is most frequently related to improper device maintenance, commonly battery failure. EMT-Basics must assure proper battery maintenance and battery replacement schedules.
G. Training and sources of information - the American Heart Association publishes a variety of guidelines and additional information on automated external defibrillation.
H. Maintenance of skills - most systems permit a maximum of 90 days between practice drills to reassess competency in usage of AEDs.
I. Medical direction
1. Successful completion of AED training in an EMT-Basic course does not permit usage of the device without approval by state laws/rules and local medical direction authority.
2. Every event in which an AED is used must be reviewed by the medical director or his designated representative.
3. Reviews of events using AEDs may be accomplished by: a. Written report. b. Review of voice-ECG tape recorders attached to AED's. c. Solid-state memory modules and magnetic tape recordings stored in device.
J. Quality improvement - involves both individuals using AEDs and the
EMS system in which the AEDs are used.